intermittent 126 ACC problems
 

When using the air conditioning, about 65% of the time, no air will come out the center vents like it should. Sometimes after being driven awhile it will start to but then maybe cut out again later on. Also, if trying for maximum fan speed, it's no more than the medium speed. But, after driving, sometimes it will blow harder like it should. I first noticed it during the winter when trying the defrost it wouldn't blow that hard then maybe it would blow hard later on.

The car is a 1987 300SDL. Does this sound like a PBU problem? That's what I think it is but those are pricey. Has anyone successfully resoldered theirs if that's the problem?

Thanks
David

Did you fix this problem?

When it does not come on right away - if you very slightly "jiggle" your key does it come on?